Earlier quoted context omitted.
I found that strange as well. My guess is that `npm` is just the package manager people are most likely to already have installed and doing it this way makes it easy. They might think asking people to install Cargo is too much effort. Wonder if the pattern of using npm to install non-node tools will keep gaining traction.
Why not just downloadable binary then?
Their Github releases provides the binaries, as well as a `curl ... | sh` install method and a guide to use github releases attestation which I liked.